What does Langelier index mean?

The Langelier Index is an approximate indicator of the degree of saturation of calcium carbonate in water. It is calculatedOpens in new window (58 KB) using the pH, alkalinity, calcium concentration, total dissolved solids, and water temperature of a water sample collected at the tap.

What does a negative Langelier index reading indicate about a water?

If LSI is negative: No potential to scale, the water will dissolve CaCO. If LSI is positive: Scale can form and CaCO3 precipitation may occur. If LSI is close to zero: Borderline scale potential. Water quality or changes in temperature, or evaporation could change the index.

What does LSI mean in water treatment?

Langelier Saturation Index
Langelier Saturation Index (LSI) is a set of water parameters that provide stability to the water by being used as an indicator of the corrosivity of the feed water.

How can I reduce my LSI?

Add muriatic acid to decrease the pH and LSI value.

How is water corrosivity measured?

The potential for water to be corrosive is measured by three different indexes: the Langelier Saturation Index (LSI), the Potential to Promote Galvanic Corrosion (PPGC), and the Larson Ratio (LR).

Why is carbon dioxide added to pool water?

Adding CO2 to the water creates chemical a balance because it helps to form carbonates and bicarbonates. This composition increases the chances that solids will dissolve in the water. Fortunately, CO2 won’t make the pool more alkaline; alkalinity often leads to corrosion.

What is Langelier Index & Ryznar Stability Index?

The Ryznar index is based loosely off of the Langelier saturation index that was created in the 1930s. The Ryznar index is logarithmic, similar to other indices that are used to calculate calcium carbonate formation. Generally, any value above 6 indicates that the water is likely to form a calcium carbonate scale.

What is corrosivity measured in?

What should LSI be?

In short, the LSI tells us how saturated our water is with calcium carbonate (CaCO3). Perfect saturation is 0.00 LSI, and the acceptable range is between -0.30 to +0.30 LSI. If the LSI is -0.31 or below, water is aggressive because it is under-saturated with calcium carbonate.

What should the LSI of a pool be?

The water . If LSI Index is between -0.3 and +0.3 pool water is Balanced. When pool water is balanced, it has no effect on the pool or equipment. There are two values you can readily change to help improve your LSI value to get it into the optimum range: pH and Alkalinity level.

At what pH is water corrosive?

Water that is moderately alkaline (40 to 70 mg/L) with a pH between 7.0 and 8.2 is usually not corrosive. Water with a pH below 6.5 will be corrosive, especially if alkalinity also is low. However, water with pH values above 7.5 also can be corrosive when alkalinity is low.

What is the Langelier Index (LSI)?

The Langelier Index isdefined as the difference between actual pH (measured) and calculated pHs. Themagnitude and sign of the LSI value show water’s tendency to form or dissolve scale,and thus to encourage corrosion.

What is Langelier Saturation Index in chemistry?

Langelier Saturation Index (LSI) The Langelier Saturation index (LSI) is an equilibrium model derived from the theoretical concept of saturation and provides an indicator of the degree of saturation of water with respect to calcium carbonate. Water with a Langelier saturation index of 1.0 is one pH unit above saturation.

What is the Langelier Index of calcite?

LSI is defined as: pH s is the pH at saturation in calcite or calcium carbonate and is defined as: B = -13.12 x Log 10 ( o C + 273) + 34.55 C = Log 10 [Ca 2+ as CaCO 3] – 0.4 Click here to see an example of a Langelier Index calculation.

What does near-zero Langelier Index mean?

Near-zero LI – Water is saturated with calcium carbonate; neither strongly scale forming or corrosive. The Langelier index is only an approximation of the tendency, but not a direct measure of the corrosive nature of the water. However, it is a very useful tool for showing this tendency.